title: [Validity of the assessment of urinary protein excretion by spot urine in patients with chronic kidney disease].
abstract: OBJECTIVE
  We investigate the validity of the assessment of urinary protein excretion by spot urine samples collected by different methods in outpatients with chronic kidney disease (CKD). SUBJECTS AND METHODS We obtained 24-hour urine and two spot urine samples, including the first morning urine and daytime urine in 159 CKD patients. Urinary protein excretion was assessed by the protein/creatinine ratio from spot urine samples (morning: m-UP (g/gCr), daytime: d-UP (g/gCr) ]. We examined the correlations and the differences among m-UP, d-UP and the actual urinary protein excretion obtained by 24-hour urine (a-UP(g/day) .
  
  
  RESULTS
  Significant correlations were found between m-UP and a-UP, and between d-UP and a-UP (r = 0.88, 0.85; p < 0.001). Correlations between m-UP and a-UP were greater relative to those between d-UP and a-UP in patients with less than 3.5 g/day of a-UP and in patients with CKD stages 1 to approximately 3. The percent difference between m-UP and a-UP was--16.0 +/- 40.5%, and that between d-UP and a-UP was 27.1 +/- 72.9%. The absolute value of the percent difference between d-UP and a-UP tended to be greater than that between m-UP and a-UP (34.9 +/- 25.9% vs. 49.9 +/- 59.9%, p = 0.06).
  
  
  CONCLUSIONS
  Urinary protein/creatinie ratio of the first morning urine is better approximate the urinary protein excretion obtained by 24-hour urine compared with that of spot urine in the daytime.
authors.affiliation: Department of Nephrology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Ami
authors.initials: A
authors.lastname: Hayashi
authors.forename: Tomonari
authors.initials: T
authors.lastname: Okada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Yume
authors.initials: Y
authors.lastname: Nagaoka
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Wada
authors.forename: Asako
authors.initials: A
authors.lastname: Gondo
authors.forename: Tomoka
authors.initials: T
authors.lastname: Nango
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Miyaoka
authors.forename: Kanna
authors.initials: K
authors.lastname: Watanabe
authors.forename: Azusa
authors.initials: A
authors.lastname: Iwata
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Nakao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000652:urine*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000652:urine*; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000652:urine*
chemical_list: D003404:Creatinine